If you have been diagnosed with cancer that is contained within the prostate, you may be thinking:
“Hey, there’s just a spot of cancer that showed up on the MRI,” or:
“Only three of the needles came back with any cancer at all.”
And this may lead you to think: “Why do we have to treat the whole thing? Why can’t I just get a prostate version of a lumpectomy?”
Or: “Why not just zap that one spot of cancer?”
Wouldn’t that be great?
This is called focal therapy – just treating part of the prostate. In just a few seconds on the internet, you can see that there’s a lot of this focal therapy out there, and it all sounds great! No erectile dysfunction (ED) or urinary incontinence! If your PSA rises, no problem! Treat it again! A lot of doctors are offering focal treatment, using methods including cryotherapy (freezing the tissue), high-intensity focused ultrasound (HIFU), or even with highly focused radiation.
There’s just one problem with every type of focal therapy for prostate cancer, says University of Michigan radiation oncologist and Prostate Cancer Foundation (PCF)-funded investigator Daniel Spratt, M.D.: “I would say, strongly, that it’s experimental. There’s a very high risk of recurrence, usually within the first three years and it may increase your risk of side effects if you later need curative treatment. There is a reason it is not considered a standard-of-care treatment by most national and international guidelines.”
Prostate cancer is usually a multi-focal disease, meaning it is in more than just 1 or 2 spots in your prostate. This is true even if your biopsies or MRI show only 1 area being involved with cancer. Some studies suggest >40% of patients have MRI-invisible tumors, and standard prostate biopsies sample <1% of your prostate gland. This is why focal therapy is often ineffective – it treats only part of your cancer.
Also, a lot of what they say about not having side effects is not true. “Side effects are often lower than men experience with a radical prostatectomy, but there are side effects,” says Spratt. “There’s still the potential for erectile dysfunction (ED) and other side effects, and one of the biggest concerns is that with subsequent treatment, if the patient needs surgery or radiation, sometimes you can have severe or unexpected side effects. I’ve seen it in patients who previously had focal therapy,” including one man after HIFU, whose entire urethra (the tube that carries urine from the bladder through the prostate and into the penis) became necrotic – the tissue died. “He had to have emergency surgery. They killed healthy tissue.”
That’s why focal therapy for prostate cancer is still considered experimental. “At the PCF, ‘experimental’ means ‘not proven,’” says molecular biologist and medical oncologist Jonathan Simons, M.D., CEO of the PCF.
Why is it not yet proven? This requires well-designed studies to see how patients do in the short run and then over several years. “There’s so little evidence in the literature,” says Spratt, and most are retrospective studies or small single arm trials. “No well-powered trials with long-term follow-up have been done to even inform us of how effective these therapies are, and to show the safety of doing subsequent curative treatment (surgery or radiation).”
Spratt has seen many men in recent years who have come from around the country to see him after focal therapy has failed. “Most of the patients I see who have had it are very upset. Insurance often does not cover it, and they have spent $20,000-$30,000 out of pocket, thinking they’re going to get a cure with no side effects. But some do get side effects and all of them who see me were not cured. And when I tell them, ‘Look, you need a second treatment and you’re at a higher risk of having more side effects,’ they are very upset.”
The best way to try focal therapy, Spratt continues, is in a clinical trial, “where you are fully informed of all the risks. Many top centers offer focal therapy, and they should be offering it in the context of a clinical trial. If not, this is concerning. These trials are critical to learn how to quantify and optimize focal therapy. Maybe if they improve it, in the years to come, it will be better than surgery or radiation. But right now, it’s definitely not. We’re learning. There’s a lot of misinformation out there. We must remember that if patients want a non-invasive option other than radical surgery, there are multiple forms of radiotherapy that are completely non-invasive and have better cure rates and long-term potency rates than focal therapy.”
In a recent trial of HIFU, “within one year, about 30 percent of men developed ED and 25 percent still had cancer in their prostate. Most of these men had low- or intermediate-risk disease, and could safely have been monitored on active surveillance. In comparison, in a similar risk group of patients receiving radiotherapy, one would expect close to zero percent chance of recurrence within one year, no incontinence, and fewer than 10 percent would experience ED so soon. Similarly, surgical removal of the prostate would also have excellent long-term cure rates.
“So why do centers and providers offer focal therapy? This is very complex. I fear it comes back to money, trying to advance one’s academic career with something different, and the pervasive avoidance of working as a multi-disciplinary team. A lot of doctors are trying to offer something less invasive than removal of the prostate for patients looking to avoid the risks of incontinence or impotence, rather than simply offering radiotherapy. Focal therapy is new and it entices patients – like they found the magic bullet. However, external-beam radiotherapy has extensive, high-quality evidence with very long-term follow-up beyond 20 years, and has essentially zero percent incontinence and superior erectile function outcomes compared to the focal therapy literature.”
Spratt says, “Bottom line: the two standard-of-care treatments for prostate cancer are surgery and radiotherapy. Lots of emerging treatments and technologies, including focal therapy and proton-beam therapy, may have a role for the management for prostate cancer. Well-done randomized trials are necessary to determine what, if any, role they will have in the management of prostate cancer. Until then…proceed with caution.”
Overview
Focal One® High-Intensity Focused Ultrasound.
What is focal therapy for localized prostate cancer?
Focal therapy is a treatment for prostate cancer of low to intermediate aggressiveness that is completely contained (localized) within the prostate.
For many years there have been two main approaches to managing localized prostate cancer. The first is active surveillance or “watchful waiting.” In cases of older men or low-risk patients, regular medical tests are conducted to make sure the cancer isn’t spreading. No other action is taken because the cancer is stable or growing so slowly it won’t cause problems right away. If tests show the cancer is spreading, treatments can begin. Of those men assigned to active surveillance, about one-third will eventually need to have surgery or radiation.
The second approach to treating localized prostate cancer has been the use of radiation or surgery. This is effective for removing any tumors present but is typically associated with side effects in the urinary, sexual, and bowel function. Two common side effects include loss of control over urinary functions (incontinence) and erectile dysfunction
Focal therapy offers a middle-ground treatment. The idea behind focal therapy is to preserve these functions while still treating the cancer effectively. Focal therapy concentrates on treating “the index lesion,” which is usually defined as a tumor visible on MRI of low or favorable intermediate grade Even though many cases of prostate cancer have more than one tumor site, some researchers believe that the index lesion is what drives and predicts how any particular cancer will progress. If growth of the index lesion can be controlled with focal therapy, the thought is that the cancer as a whole can be managed safely while minimizing side effects.
What treatments are used in focal therapy for localized prostate cancer?
Focal therapy uses ablation, which is the use of extreme temperatures to destroy tissue. In focal ablation, the area of the prostate that contains the index lesion is targeted, rather than treating the entire prostate gland. Focal ablation techniques include:
- Cryotherapy: The use of very cold gases passed through needles to freeze and destroy cancer tissue.
- HIFU (High Intensity Focused Ultrasound): The use of high-frequency sound waves directed at the tumor through an ultrasound probe inserted into the rectum. The high intensity waves cause the diseased tissue to heat up and die.
- Photodynamic therapy: A drug called a photosensitizer is injected into the bloodstream. This drug then absorbs light rays directed at the tumor, and produces an active form of oxygen that destroys cancer cells.
- Laser ablation: The use of laser radiation energy pinpointed to a very small area to burn away cancerous tissue. Some laser ablation has the advantage of being able to be performed at the same time as magnetic resonance imaging (MRI), allowing very specific targeting and also real-time views of results.
When focal therapy for prostate cancer first began to be used in about 2007, it was only as an alternative to active surveillance in very low-risk patients. Since then, the use of focal therapy has expanded to include those with favorable intermediate risk disease (as defined by the NCCN guidelines). The best candidates have a prostate gland of about 40cc in size or a tumor in the lower half of a larger gland, a single visible tumor on MRI, and the absence of cancer elsewhere in the gland (as proven by biopsies).
In each case, the doctor will consider the patient’s general health and mental outlook, the size and location of the tumors present, and their chances of spreading more. Use of tests such as MRI, ultrasound, and biopsy (tissue samples examined in the laboratory) can help decide if a patient will benefit more from focal therapy or from traditional treatments.
